Float switch with auxiliary circuit control



3 M. E. HENNING FLOAT SWITCH WITH AUXILIARY: CIRCUIT CONTROL Filed Sept. 2, 1931 CURRENT S PLY WA TE R \S PPLV Patented Jan. 9, 1934 FLOAT SWITCH WITH AUXILIARY CIRCUIT CONTROL Malcolm E. Henning, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines, Iowa,

a corporation of Iowa Application September 2, 1931. Serial No. 560,781

8 Claims. (Cl. 200-84) An object of my present invention is to provide a float switch of simple, durable and inexpensive construction having an auxiliary circuit control for an alarm or the like.

6 Still a further object is to provide a control switch structure with an auxiliary circuit control, the source of current supply for said auxiliary circuit being independent of the current supply for the switch structure whereby an alarm may be given or a safety device may be operated when there is a current failure of the current supply for the switch structure due to power house trouble, or where the switch structure is applied to a float for actuation therefrom and controls a pump, the alarm may be given in case of pump or pump motor trouble or because of water failure, which might result in a boiler running dry, thus making possible an explosion.

More particularly it is my object to provide a switch structure in which a control switch is automatically opened and closed and in which auxiliary or alarm contacts are provided which are engaged after the control switch has moved to one of its positions.

26 Another object is to provides. float actuated control switch with mechanism which actuates alarm contacts to closed circuit position after the control switch has been operated to one of its positions and whereupon the water level continues to fall because of current supply failure, pump or motor trouble or water supply failure.

Another object is to provide in a float switch structure an automatically movable lever which engages a switch arm and which, after disengag- 36 ing from the switch arm because of excessively low water level, will cause actuation of an alarm device. I

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illusfirated in the accompanying drawing, in which:

Figure 1 is a side elevation of 'a float cage with my float switch mounted thereon and showing diagrammatically a control and an alarm circuit and mechanism operated by the control circuit.

Figure 2 is an enlarged view of the switch structure in Figure 1 with the cover for the switch casing removed.

Figure 3 is a partial. sectional view on the line 3-3 of Figure 2.

Figure 4 is a perspective view of a resilient lever 55 used in the switch structure; and

Figure 5 is a diagrammatic view of the alarm circuit.

On the accompanying drawing I have used the reference numeral 10 to indicate a float cage. A float arm cage 12 is secured thereto by means of bolts 14 and flanges 16 and 18. 7

Within the float cage 10 a float 20 is secured to a float arm 22. The float arm 22 is connected with a rock shaft 24 which extends through a packing gland 26. An actuating lever 28 is secured to the outer end of the rock shaft 24.

My switch structure with auxiliary circuit control is indicated generally by the reference character A. It is mounted on a Z-shaped bracket 30 which is secured to a boss 32 of the float arm cage 12 by screws 34. Screws 36 serve to retain the switch structure A on the bracket 30.

The switch structure A includes a casing 38 and a cover 40. Within the casing 38 a switch arm 42 is provided and pivoted at 44. The switch 78 arm 42 is of iron or the like and constitutes an armature for a permanent horse-shoe magnet 44'. The switch arm 42 carries a movable contact 46 for engagement with a stationary contact 48.

Pivoted on the pin 44 is a resilient lever 50 of bell crank shape, the upper end of which is adapted to engage the switch arm 42 and move it in a right hand direction (see Figure 2) for separating the contacts 46 and 48. The opposite end of the resilient lever 50 is slotted as indicated at 52 to coact with a reduced portion 54 of an adjusting screw 56. The adjusting screw has heads 58 and 60 on opposite sides of the resihent lever 50 and ears 62 engage opposite flats of the head 58 to prevent rotation of the adjusting screw 56 rel-= ative to the lever 50.

A light spring 64 serves to constrain the upper end of the lever 50 toward engagement with the switch arm 42. A movable alarm contact 66 is carried by the upper end of the resilient lever 50 and is adapted to coact with a stationary alarm contact 68. The contact 68 is screw threaded in a boss 70 of a fitting 72 which is mounted stationarily relative to the casing 38 by a screw '74. Flexible leads '76 and '78 extend from the contacts 66 and 68 into a connection box 80 wherein they may be connected with alarm circuit wires.

A flexible lead 82 connects the armature or switch arm 42 with a terminal 84 whereby the contact 46 is connected with such terminal while the contact 48 is connected with a terminal 86. The terminals 86 and 84 are for a control cir-' cuit.

The adjusting screw 56 is threaded in a post 88 which is slidable through a sleeve 90. The sleeve 11o is supported relative to the casing 38 as best shown in section in Figure 3. It is provided with opposite slots 92 in which a cotter pin 94 slides, thus holding the post 88 nonrotatable relative to the sleeve 90.

A screw 96 is connected with the post 88 and extends from the lower end thereof through a slot in the actuating arm 28. Adjusting nuts 98 on opposite sides of the actuating lever 28 provide for a lost motion connection to widen the differential of operation of the switch structure.

Practical operation The herein disclosed switch structure is adapted for various installations, one of which is shown in Figure 1. The control circuit wires are indicated at 100. They energize a pump motor 102 which operates a water pump 104. The water pump 104 supplies water to a boiler 106. v

The level of water in the float cage 10 which is connected with the boiler 106 actuates the float 20 and consequently the switch arm 42 to open and closed positions. When the float rises the resilient lever 50 first engages the switch arm 42, then bends slightly because of the pull of the magnet 44 on the switch arm and finally the stored energy in the spring 50 causes movement of the arm 42 toward open circuit position. This movement is accelerated because of the arm immediately moving through an ever weakening magnetic field and the spring 50 flexing to its original straight position. This de-energizes the motor 102 and after steam is generated and taken from the boiler 106 the water level lowers until the actuating lever 28 engages the lower nut 98 and pulls the post 88 downwardly, allowing the magnet 44 to draw the arm 42 into position with the contacts 46 and 48 engaged. When the contacts are thus engaged if there is no current for the motor 102 because of current failure or if the motor is inoperative or the pump mechanism inoperative to pump water to the boiler because of a break-down of the pump or failure of the water supply, then the float 20 will continue to move downwardly.

After slight further movement from the position shown in Figure 2, the contacts 66 and 68 will become engaged, which closes the alarm circuit though the leads 76 and '78 which are connected with an alarm device, such as a bell 108 and a source of current supply 110, such as dry cells, which are independent of the current supply for the motor 102. Thus the auxiliary contacts actuate an alarm circuit to notify the operator of various troubles and provide a much desired safety feature for a float switch or other automatically operated switch.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

1. For use with a movable actuating member, a switch structure comprising a casing, a post slidable through a wall of said casing and operatively connected with said actuating member for simultaneous movement therewith, a movable switch member within said casing, a resilient lever operatively connected with said post and engageable with said switch member, a magnet infiuencing said switch member toward such engagement and alarm contacts in sa d casi one of ,said alarm contacts being carried by said resilient lever and the other one being stationary relative to said casing, said alarm contacts being engageable only after disengagement of said resilient lever from said switch member.

2. For use with a movable actuating member, a switch structure comprising a casing, a movable switch member within said casing, a resilient lever operatively connected with said actuating member and engaging said switch member, a magnet influencing said switch member toward such engagement and alarm contacts in said casing, one of said alarm contacts being carried by said resilient lever and the other one being stationary relative to said casing, said alarm contacts being engageable only after disengagement of said resilient lever from said switch member.

3. For use with a movable actuating member, a switch structure comprising a casing, a movable switch member within said casing, a resilient lever operatively connected with said actuating memebr and engaging said switch member, means for causing such engagement between said resilient member and said switch member and alarm contacts, one of said contacts being carried by said resilient lever and the other one being stationary relative to said casing, the first mentioned contact being engageable with the second mentioned one only after disengagement of the resilient lever from said switch member.

4. For use with a movable actuating member, a switch structure comprising a movable switch member, a lever operatively connected with said actuating member and engageable with said switch member, means for normally maintaining such engagement, alarm contacts, said alarm contacts being engageable with each other after disengagement of said lever from said switch member.

5. In a control switch, switch mechanism automatically movable, means for moving said switch mechanism to open and closed circuit positions, alarm contacts operatively connected with said movable means whereby they are engaged after said switch mechanism has been moved to one of its positions and when the mov able means continues to move in thesame direction after moving the switch mechanism to such position.

6. In a control switch, switch mechanism including an arm, a sleeve, an actuating post slidable therethrough, a screw threaded in said actuating post and operatively but non-rotatably connected with said switch actuating arm, said sleeve having a slot therein, a removable pin extending from said actuating post and slidable in said slot, means for moving said actuating post and thereby said switch operating arm to open and closed circuit positions and alarm contacts operatively connected with said actuating post whereby they are engaged after said switch arm has been moved to closed circuit position and when the actuating post continues to move in the same direction after moving the I switch arm to such position.

anism to open and closed circuit positions, said means including an adjusting screw having an angular head between said ears and engaged therebyto normally prevent rotation of said adlusting screw and alarm contacts operatively connected with said arm whereby they are engaged after said switch mechanism has been moved to one of its positions and when the movable means continues to move in the same direction after moving the switch mechanism to such position.

MALCOLM E. HENNING. 

